Determination of f_s/f_d for 7 TeV pp collisions and a measurement of the branching fraction of the decay Bd->D-K+

TL;DR

This paper measures the ratio of fragmentation fractions and the branching fraction of a specific B meson decay using 7 TeV proton-proton collision data from the LHC, providing precise experimental results.

Contribution

It presents the first measurement of the fragmentation fraction ratio f_s/f_d and the branching fraction of B_d to D^- K+ decay at 7 TeV LHC energies.

Findings

f_s/f_d = 0.253 ± 0.017 (stat) ± 0.017 (syst) ± 0.020 (theo)

Branching fraction B(B_d → D^- K+) = (2.01 ± 0.18 (stat) ± 0.14 (syst))×10^{-4}

Provides key inputs for B physics and CP violation studies.

Abstract

The relative abundance of the three decay modes $B_d \to D^- K^+$, $B_d \to D^- \pi^+$ and $B_s \to D_s^- \pi^+$ produced in 7 TeV $pp$ collisions at the LHC is determined from data corresponding to an integrated luminosity of 35 pb$^{-1}$. The branching fraction of $B_d \to D^- K^+$ is found to be $\cal B (B_d \to D^- K^+) = (2.01 \pm 0.18^{\textrm{stat}} \pm 0.14^{\textrm{syst}})\times 10^{-4}$. The ratio of fragmentation fractions \fsfdt is determined through the relative abundance of $B_s \to D_s^- \pi^+$ to $B_d \to D^- K^+$ and $B_d \to D^-\pi^+$, leading to $f_s/f_d = 0.253 \pm 0.017 \pm 0.017 \pm 0.020$, where the uncertainties are statistical, systematic, and theoretical respectively.